Weight distribution hitch system with sway reduction

ABSTRACT

A weight distribution system used with a hitch on a vehicle and a trailer, the weight distribution system comprising a moment bar with a forward end attached to the hitch so as to pivot about a generally vertical axis, the moment bar extending rearwardly along a center longitudinal plane of the trailer toward a rearward portion, the moment bar configured to exert a forward moment on the vehicle in response to an upward force on the rearward portion; a bracket attached to a trailer frame element, wherein the bracket is above the first rearward portion and further from the center longitudinal plane of the trailer than the rearward portion; and a tension member combined with a tension mechanism so as to increase and decrease a tensile force between the bracket and the rearward portion, to thereby increase and decrease the upward force on the rearward portion whereby sway of the trailer is reduced by biasing the system back to the centerline when the vehicle and trailer are out of alignment is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNos. 62/980,962 titled “Weight Distribution Hitch System” filed on 24Feb. 2020; 62/980,966 titled “Weight Distribution Hitch System” filed on24 Feb. 2020; 62/980,969 titled “Weight Distribution Hitch System” filedon 24 Feb. 2020; 62/980,976 titled “Weight Distribution Hitch System”filed on 24 Feb. 2020; 62/980,978 titled “Weight Distribution HitchSystem” filed on 24 Feb. 2020; 62/980,990 titled “Weight DistributionHitch System” filed on 24 Feb. 2020; 62/980,994 titled “WeightDistribution Hitch System” filed on 24 Feb. 2020; 62/980,999 titled“Weight Distribution Hitch System” filed on 24 Feb. 2020; 62/981,002titled “Weight Distribution Hitch System” filed on 24 Feb. 2020; and62/981,003 titled “Weight Distribution Hitch System” filed on 24 Feb.2020, each of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to trailer hitches. More particularly, itrelates to trailer hitches equipped with weight distribution systems.

BACKGROUND

A typical trailer hitch connects to a vehicle near its rear bumper. Whenthe trailer is connected, the downward load from the trailer tongue onthe hitch can cause the vehicle to squat, putting extra load on the rearaxle and lessening the load on the front axle. This can reduce thetraction of the front tires and can cause the headlights to pointupward. Equalizer hitches can prevent these problems by using springbars to exert a moment on the vehicle, which shifts the resulting loadof the trailer tongue toward the center of the vehicle, eliminating thesquat. However, equalizer hitches require tedious setup and are noteasily adjusted. Changes to the tow vehicle, the trailer, or the loadcarried by the trailer may require readjustment. These adjustments taketime and may require special tools. Because of this, users may eitherfail to adjust or adjust incorrectly. Accordingly, a hitch that iseasier to set up and adjust is desirable.

SUMMARY

In a first aspect, the disclosure provides a weight distribution systemused with a hitch on a vehicle and a trailer, the weight distributionsystem comprising a moment bar with a forward end attached to the hitchso as to pivot about a generally vertical axis, the moment bar extendingrearwardly along a center longitudinal plane of the trailer toward arearward portion, the moment bar configured to exert a forward moment onthe vehicle in response to an upward force on the rearward portion; abracket attached to a trailer frame element, wherein the bracket isabove the first rearward portion and further from the centerlongitudinal plane of the trailer than the rearward portion; and atension member combined with a tension mechanism so as to increase anddecrease a tensile force between the bracket and the rearward portion,to thereby increase and decrease the upward force on the rearwardportion whereby sway of the trailer is reduced by biasing the systemback to the centerline when the vehicle and trailer are out ofalignment.

In a second aspect, the disclosure provides a weight distribution hitchsystem comprising a lifting mechanism; a moment bar pivotally connectedabout a vertical axis to a hitch coupling; and a linkage bar with a rearportion connected to the trailer and a front portion adapted to interactwith the lifting mechanism; wherein a rear portion of the moment bar ispivotally connected about a lateral axis to the linkage bar such thatwhen the lifting mechanism lifts on the front portion of the linkagebar, the rear portion of the moment bar is raised and induces a forwardmoment on the hitch coupling.

Further aspects and embodiments are provided in the foregoing drawings,detailed description, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are provided to illustrate certain embodimentsdescribed herein. The drawings are merely illustrative and are notintended to limit the scope of claimed inventions and are not intendedto show every potential feature or embodiment of the claimed inventions.The drawings are not necessarily drawn to scale; in some instances,certain elements of the drawing may be enlarged with respect to otherelements of the drawing for purposes of illustration.

FIG. 1 is a side elevation view of a first exemplary embodiment of aweight distribution hitch system according to the present disclosure.

FIG. 2 is a perspective view of a second exemplary embodiment of aweight distribution system including a moment bar with an apertureaccording to the present disclosure.

FIG. 3 is a perspective view of a third exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 4 is a perspective view of a fourth exemplary embodiment of aweight distribution hitch system according to the present disclosure.

FIG. 5 is a side view of the fourth exemplary embodiment.

FIG. 6 is a bottom view of the fourth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 7 is a side view of a fifth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 8 a top view of a sixth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 9A is a side view of a seventh exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 9B is a side cross-sectional view of the embodiment of FIG. 9A.

FIG. 9C is an exploded view of embodiment of FIG. 9A.

FIG. 10 is a top view of an eighth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 10A is a cross-sectional view of the embodiment of FIG. 10 takenalong the line A-A in FIG. 10 .

FIG. 10B is a side view of the embodiment of FIG. 10 .

FIG. 10C is a bottom view of the embodiment of FIG. 10 .

FIG. 11 is a side view of a ninth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 12 is a side view of a tenth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 13 is a top view of the embodiment of FIG. 12 .

FIG. 14 is a side view of the embodiment of FIG. 12 with the weightdistribution adjusted.

FIG. 15 is a bottom view of the embodiment of FIG. 12 .

FIG. 16 is a top view of an eleventh exemplary embodiment of a weightdistribution system according to the present disclosure.

FIG. 17 is an isometric side view of the embodiment of FIG. 16 .

FIG. 18 is a side view of a twelfth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 19 is a front view of a thirteenth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 20 is s bottom view of the embodiment of FIG. 19 .

FIG. 20A is close-up view of the moment arm and cable in the embodimentof FIG. 20 .

FIG. 21 is a side view of a fourteenth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

FIG. 22 is a side view of a fifteenth exemplary embodiment of a weightdistribution hitch system according to the present disclosure.

DETAILED DESCRIPTION

The following description recites various aspects and embodiments of theinventions disclosed herein. No particular embodiment is intended todefine the scope of the invention. Rather, the embodiments providenon-limiting examples of various compositions, and methods that areincluded within the scope of the claimed inventions. The description isto be read from the perspective of one of ordinary skill in the art.Therefore, information that is well known to the ordinarily skilledartisan is not necessarily included.

Definitions

The following terms and phrases have the meanings indicated below,unless otherwise provided herein. This disclosure may employ other termsand phrases not expressly defined herein. Such other terms and phrasesshall have the meanings that they would possess within the context ofthis disclosure to those of ordinary skill in the art. In someinstances, a term or phrase may be defined in the singular or plural. Insuch instances, it is understood that any term in the singular mayinclude its plural counterpart and vice versa, unless expresslyindicated to the contrary.

As used herein, the singular forms “a,” “an,” and “the” include pluralreferents unless the context clearly dictates otherwise. For example,reference to “a substituent” encompasses a single substituent as well astwo or more substituents, and the like.

As used herein, “for example,” “for instance,” “such as,” or “including”are meant to introduce examples that further clarify more generalsubject matter. Unless otherwise expressly indicated, such examples areprovided only as an aid for understanding embodiments illustrated in thepresent disclosure and are not meant to be limiting in any fashion. Nordo these phrases indicate any kind of preference for the disclosedembodiment.

As used herein, “hitch” is intended to have a broad meaning, referringto the hardware connecting a vehicle to a trailer including but notlimited to a hitch receiver, a hitch shank, a hitch extension, a hitchhead, a ball mount, a ball, and spring bars or moment bars, as contextrequires. It may also be used more specifically to refer to the piecethat mounts underneath the vehicle, typically with bolts or welding, andcontains the receiving hole for the hitch shank, as context requires.

As used herein, “forward” means toward the front of a vehicle, or thedirection a vehicle travels when it is in drive and the steering wheelis in a neutral position. It also may refer to a portion of an objectthat faces that direction.

As used herein, “rearward” means the direction a car travels when it isin reverse and the steering wheel is in a neutral position. It also mayrefer to a portion of an object that faces that direction.

As used herein, “longitudinal axis” in the context of a vehicle/trailersystem, is defined by a line extending from the front of a vehicle tothe rear of the vehicle, through the centerline of the vehicle, andparallel to the ground. In the context of a single body, it may refer tothe axis which goes through the center of the longest dimension of thatbody.

As used herein, “lateral axis” is orthogonal to the longitudinal axisand parallel to the ground.

As used herein, “vertical axis” is orthogonal to both the longitudinalaxis and the lateral axis, or, in other words, straight up and down.Vertical axis may also apply to an axis which is not exactly straight upand down but is less than 15 degrees off.

As used herein, “centerplane” refers to a vertical plane on thecenterline of a vehicle or trailer from front to back.

As used herein, “forward moment” means a twisting force that would tendto tilt the front of a vehicle down and the rear of the vehicle up.

As used herein, “attachment member” means the component of a weightdistribution hitch on the vehicle side that mounts to the finalconnecting pieces which attach to the trailer, typically the ball mountor hitch head.

EXEMPLARY EMBODIMENTS

The present disclosure relates to weight distribution hitch systems.More particularly, it relates to weight distribution hitch systems thatcan be easier to attach and adjust, safer to operate, provide improvedsway control, and/or dampen porpoising among other improvements.

Conventional trailer hitches typically consist of a ball/couplerarrangement, wherein a ball is attached to a tow vehicle, the coupler isattached to a trailer, and the ball fits inside the coupler to create apivotal connection. This arrangement allows forces to be transferredbetween the vehicle and the trailer in the longitudinal, lateral, andvertical directions but does not allow any moments to be transferred.One problem with this arrangement is that the downward force from thecoupler to the ball can overload the rear axle of the vehicle, causingit to squat. This takes weight off the front wheels, which can causesteering and/or braking issues and can also angle the headlights upward.

One way to prevent this is to use a weight distribution trailer hitchthat can transfer a moment between the trailer and vehicle. A negativemoment in the lateral direction, or a “forward moment,” takes a load offthe rear axle of the vehicle and distributes it to the front axle. Thisreduces the squat of the vehicle.

However, typical weight distribution hitches can be tedious to hook upand adjust. They involve many connections including multiple steps ateach connection and even raising and lowering the trailer multipletimes. Standard weight distribution hitches have two spring bars thatextend from the back of the vehicle along the frame of the trailer.These bars are used to create a forward moment on the hitch thatdistributes the weight toward the vehicle's front tires. In order to dothat, they are attached to the frame of the trailer under extremestress, typically with chains. The length of the chains and/or the angleof the ball mount of the hitch must be adjusted so, when the trailer isconnected, the correct moment is applied. To verify it is correct,measurements must be taken and compared to the system in an unloadedstate. This is typically the distance between the front bumper and theground. The adjustment step cannot be performed while the weightdistribution hitch is connected, so everything must be disconnected eachtime an adjustment must be made in a tedious trial and error process.This can be fairly often if items are being added or removed from thetrailer, the vehicle, or additional trailers in a double-tow scenario.Additionally, the user typically steps over the hitch many times duringeach setup, which can be hazardous.

The preferred embodiment of the disclosed system greatly reduces thecomplexity of the setup and adjustment process by reducing the number ofparts, simplifying the connection process, allowing adjustments to bemade without disconnecting any brackets or couplers, and by allowing auser to complete the setup on a single side of the hitch. Further,adjustments can be made without raising and lowering the trailermultiple times. Because there are no chains or chain brackets, there arefewer parts resulting in cost savings. Costs can be further reducedbecause many of the remaining parts can be smaller, such as the momentbar and the attachment member. The preferred embodiment can also improvesafety by allowing the entire process to be completed on one side of thetrailer.

The disclosed system is useful on many types of connections between avehicle and a trailer where the trailer imposes a downward force on therear of the vehicle, such as a ball and coupler hitch or a pintle hitch.In the preferred embodiment, a vehicle has a rear mounted hitch with aball, and a trailer has a frame mounted coupler which latches onto theball. In one embodiment, a hitch shank and/or a ball mount has holes ina vertical row allowing the ball to be adjustable relative to theground. In other embodiments, the ball may be adjustable relative to theground with other adjustable mechanisms, or it may be fixed. In oneembodiment, pins or bolts may be used connect the ball mount to thehitch shank.

In a preferred embodiment, the moment bar extends from the attachmentmember rearward toward the trailer. In one embodiment, the moment bar isconnected to the lower rear portion of the ball mount such that it mayimpose a moment on the vehicle about a lateral axis. The moment bar maybe hingedly connected to the ball mount about a vertical axis so it canrotate side to side as the vehicle goes around corners.

One advantage of the preferred system is that the single moment bar isnot only easier to connect than dual moment bars, but it is muchshorter, allowing for less material and cost savings. The moment bar maybe installed on both the vehicle side and the trailer side while theuser is in a single position. Also, because there is preferably a singlemoment bar, which typically lies substantially on the centerline of thevehicle, the imposed moment is evenly distributed over the front tiresof the vehicle. While it is possible for dual moment bars which areevenly spaced and have the same applied forces to achieve a balancedmoment on the vehicle, any discrepancy in the angle of the moment barsor the tension in the chains will impose an imbalanced moment on thevehicle.

In one embodiment, the hinged moment bar connection may also serve assway control for the trailer. Rather than rotating freely, the hingedconnection may be resistive to being rotated, for example by promotingfriction between the moment bar and the ball mount. Steel on steel isideal in some applications of the invention because of its highcoefficient of friction, but it comes with the drawback of corroding.Passive materials, which are less corrosive, such as brass, bronze,brake pad materials, and stainless steel, also may be used. Many ofthose materials, however, have less friction than steel. Someembodiments include replaceable wear plates, which allow a user toreplace them if they become too worn. Alternatively, one or more springsare incorporated into the design to bias the moment bar to the neutralposition, i.e., extending straight back from the ball mount. In thisway, the moment bar can pivot, but that pivoting is resisted, and themoment bar is biased back to the neutral position. Incorporating aresistance into the pivoting of the moment bar can help keep the trailerfrom swaying from side to side as the resistance inhibits the lateralmovement of the trailer.

The rearward end of the moment bar is configured to receive an upwardforce. Because the forward end is fixed on a vertical axis, the upwardforce on the rearward end creates a moment on the attachment member. Inone embodiment of the invention, the force is created by a liftingmechanism which is secured to the frame of the trailer. In a preferredembodiment, the lifting mechanism is a jack which has a bearing surfacedisposed near the bottom of a shaft that extends from the trailer frameat least as far as the moment bar. One benefit of using a jack is thatit may also be used as a support for the trailer. In one embodiment, thejack is capable of being loaded in both tension and compression: tensionwhile it is lifting on the moment bar and compression while it issupporting the trailer.

The system also preferably includes a bearing surface on the liftingmechanism designed to allow it to lift on the moment bar. In oneembodiment, a jack has a bearing plate fixed to the shaft at a locationat least as low as the bottom of the moment bar. In other embodiments,the bearing surface is spherical or another curved shape. The bearingplate may attach to the outer circumference of the shaft of a jack andsurround the shaft, or it may attach to one side. In the preferredembodiment, the bearing surface of that plate is convex, which allows itto avoid point forces on the moment bar that the edge of a flat platewould create as the vehicle travels over a hill causing the two bearingsurfaces to be unparallel. In one embodiment, the moment bar has aconcave surface to better mate with the convex surface of the jack. Inanother embodiment, the mating surfaces are a ball and coupler similarto the ball and coupler connecting the hitch and trailer frame.

The moment bar preferably also contains an aperture allowing it to goaround the shaft of the jack or a portion of the jack or other liftingmechanism. This allows the bearing surface of the moment bar to surroundthe jack. This has many benefits. First, it allows the tension in theshaft of the jack to be axial rather than eccentric as it would if thebearing surface were only on one side of the jack. It also locks themoment bar onto the jack which allows it to be stored on the trailerrather than the vehicle. It also prevents theft. In one embodiment, theaperture is oval or an elongated slot. This gives the moment bar moremovement respective to the jack than with a circular aperture, whichhelps a user manipulate the moment bar into and out of its installedposition in the attachment member.

In one embodiment, an indicator or switch tells the user or a controllerwhen the vehicle or trailer is level. The level may be controlled inmany ways, including visually, mechanically, and with sensors andcontrolling circuitry. To control it visually, a user, after hooking thevehicle to the weight distribution hitch and trailer, may increase thetension in the jack while watching the level of the vehicle or thetrailer look level. Mechanically, the user may increase the tension inthe jack until a level switch or scale cuts the power to the jack, oruntil a scale or level indicator indicates that the user should stopadding tension to the jack. Sensors and controlling circuitry may beused to add or remove tension from the jack, which may comprise acontrol unit within the vehicle, on the jack, or on a personal devicesuch as a phone. In any case, the control unit may connect to a level ora load sensor, and the on and off switch to the jack. Limit switches maybe included on the level indicator or load sensor, which communicate tothe motor of the jack to start or stop. In one embodiment, limitswitches are located on the level or load sensor. In another embodiment,limit switches are programmed into a control unit.

The additional load from the lifting mechanism can be measured in manydifferent places. It may be measured within a trailer jack, the trailercoupler, or on the hitch, as disclosed in patent number U.S. Pat. No.7,960,659 B2, which is hereby incorporated by reference in its entirety.It may also be measured within the ball of the hitch as disclosed in USpatent publication number US 2006/0290102 A1, which is herebyincorporated by reference in its entirety.

In one embodiment of the invention, the load on the moment bar ismeasured by the tension in the jack as measured by the resistance to anelectric motor controlling the jack. This is typically done by measuringthe amperage to the motor, as the amperage is directly related to theload on the motor. The amperage meter wirelessly communicates viaBluetooth or other wireless means to a controlling device, such as aphone. The controlling device may have access to data determining whatthe maximum load on the motor should be either locally or throughnetwork communication. The user device communicates wirelessly with apower switch on the motor and stops the motor when the desired load isreached. In other embodiments, a scale or level replaces the amperagemeter as the measuring device that communicates with the user device.

Another advantage of the preferred system is that it can be adjustedwhen the vehicle is in motion. Weight distribution hitches maintain adesirable forward moment on the vehicle that is typically dependent onthe vehicle and trailer being on flat ground. When a vehicle with aweight distribution hitch goes over a hill or a bump, the forward momentfrom the device can be undesirable. If the vehicle goes over a hill, themoment will be decreased causing the front of the vehicle to aim upward.This is especially dangerous if the vehicle is driving at night, and theheadlights are pointed upward as the driver needs to see downward.Conversely, if the vehicle drives through a depression in the ground,the moment will be increased and will force the front of the vehicledownward. This can be especially dangerous if the pressure on the rearwheels is reduced to the point that they lose traction, or even worse,if the rear wheels are lifted off the road.

One embodiment includes a weight distribution hitch that can preventthese problems by changing the weight distribution as the vehicletravels over uneven ground. In one embodiment, a load sensor indicates achange in load as the vehicle and the trailer are on uneven ground. Theload sensor may communicate wirelessly with a control unit, such as aphone or built-in processor, which may communicate with the motor on thejack to adjust accordingly. When the trailer is going over a bump orhill, the load sensor will communicate a decreased tension on the jackto the control unit which will communicate to the motor to increasetension on the jack, which will help keep the vehicle pointed level, andvice versa. Then, when the vehicle returns to flat ground, the sensorwill communicate an increased tension which will result in the controlunit reducing the tension in the jack to normal, and vice versa.

The system may also be used to prevent or reduce trailer porpoising,which is the up and down oscillation of a trailer and vehicle, inresponse, for example, to hitting a bump. This can be similar to aslinky rising and falling as it is held at each end. A load sensor orlevel sensor in the weight distribution hitch or jack will sense anincrease or decrease of load or level as the vehicle/trailer systemoscillates. In one embodiment, a load sensor in the jack is wirelesslycoupled to a control unit, such as a phone or built-in processor, in thevehicle. As the control unit receives data that the trailer isporpoising, or is in a state that could cause porpoising, the controlunit may communicate to the motor of a jack to increase tension ordecrease tension as the system may require to prevent the porpoising.When the weight distribution hitch is in a higher than normal position,a decreased tension will help lower its position. When the weightdistribution hitch is in a lower than normal position, an increasedtension will raise its position. However, to prevent porpoising, thecontrol unit may be configured to decrease tension as the hitch is in alower than normal position but raising upward, and to increase tensionas the hitch is in a higher than normal position but falling. This way,the weight distribution hitch absorbs the energy of the vehicle/trailersystem and acts as a porpoising dampener.

The system may be used with other sensors and computers to automaticallyevaluate and adjust various aspects of the weight distribution system.The following patents and published patent applications describe the useof sensors to evaluate a towed load and are incorporated herein byreference in their entireties: U.S. Pat. No. 9,290,185 titled“Determining Haul Weight” to Hall et al.; U.S. Pat. No. 9,956,965 titled“Tongue Weight Determination” to Hall et al.; U.S. Pat. No. 10,142,798titled “Arrangement for, and Method of, Locating a Mobile Device in aVenue by Inferring Transit Timer Values of Ranging Signals Received bythe Mobile Device in a Time Difference of Arrival (TDOA)-BasedUltrasonic Locationing System” to Calvarese et al.; U.S. Pat. No.10,214,222 titled “Determining Weight of a Vehicle in Reverse Gear” toHall et al.; U.S. Pat. No. 10,274,360 titled “Mobile Device VehicleWeight Determination” to Hall et al.; U.S. Pat. No. 10,543,846 titled“Determining Vehicle Power” to Hall et al.; U.S. Pat. No. 10,543,725titled “System for Determining Towing Equipment Compatibility” to Hallet al.; US 2018/0215358 titled “Auto Gain Adjusting Trailer BrakeController” to Hall et al.; US 2018/0111619 titled “Determining GrossCombined Weight” to Hall et al.; US 2019/0152468 titled “System forAutomatically Adjusting Drive Modes” to Hall et al.; US 2019/0178701titled “Monitoring System for Determining a Vehicle Safety Setting Basedon Weight” to Hall et al.; US 2019/0202251 titled “System for Optimizinga Trailer Path” to Hall et al.; and US 2019/0210418 titled “Trailer anda Tow Vehicle Path Optimization” to Hall et al.

Moment bars are typically connected to the hitch of a vehicle at aportion of the hitch located below the ball. This process may be timeconsuming and involve multiple connections. In some instances, momentbars are not removable from the hitch and remain attached to the vehicleas long as the hitch is attached. This makes the hitch very heavy,unsightly, and also creates a potential hazard for people walking nearthe rear end of the vehicle, particularly when the vehicle is notattached to the trailer, who may not see the moment bars protruding fromthe hitch. One embodiment creates an easy to connect and disconnectmoment bar apparatus to alleviate these problems.

In one embodiment, a barrel coupling comprising nesting cylindersprovides a simple connection between the hitch and the moment bars. Inone embodiment, the hitch has an outer cylinder protruding downwardbelow the hitch ball. The moment bars comprise an inner cylinder whichis inserted into the outer cylinder providing a connection which pivotsabout the z-axis and can translate a moment from the moment bars to thehitch. In an embodiment, the outer cylinder comprises a horizontalgroove on its inner surface allowing a spring clip on the inner cylinderto hold the inner cylinder inside the outer cylinder without fallingout.

The connection between the inner and outer cylinders can provide notonly a moment inducing connection, but a sliding friction which mayassist with sway control for the trailer. The materials and the gapbetween the cylinders may be varied per the needs of the system. In oneembodiment, the difference between the outer diameter of the innercylinder and the inner diameter of the outer cylinder is less than50/1000 of an inch. In another embodiment, the difference is less than30/1000 of an inch. In a preferred embodiment, the difference is lessthan 10/1000 of an inch, which provides more friction for sway controland less movement during moment transfer than a larger gap.

The size of the mating surface between the inner cylinder and the outercylinder also affects the amount of friction in the barrel coupling andthus sway control. Preferably, the inner cylinder has a diameter of atleast 2 inches. Even more preferably, the inner cylinder has a diameterof at least 2.5 inches. Yet even more preferably, the inner cylinder hasa diameter of at least 3 inches. Concerning depth, the inner and outercylinders have a mating surface that is at least 1.5 inches tall. Morepreferably, the inner and outer cylinders have a mating surface that isat least 2 inches tall. Yet even more preferably, the inner and outercylinders have a mating surface that is at least 2.5 inches tall.

Various materials provide different benefits for the sliding surfacebetween the inner and outer cylinders. In one embodiment of theinvention, both surfaces are made from steel, which is inexpensive toproduce, long lasting, and also provides a higher amount of frictionthan many other metals. In another embodiment, a liner may be applied toone of the surfaces, which may be permanent or replaceable, whichprovides more or less friction. In a preferred embodiment, the liner isbronze. In another embodiment, the liner is made from brake padmaterial. In another embodiment, for applications requiring lessfriction, the liner is oil impregnated bronze. In other embodiments, thesurfaces of the inner and outer cylinders are made from other metals orhard substances.

Another benefit is that a single hitch can comprise multiple ball sizesand also be used for weight distribution. This makes it much cheaper andeasier for users to pull multiple trailers that require different sizesof balls and that may or may not use weight distribution. With otherhitch systems, the user may have different sizes of balls, or they mayhave weight distribution, but not both.

One embodiment includes a dual coupler ball, which may be insertedthrough the barrel coupler previously mentioned such that one ballextends above the barrel coupler and the other ball is hidden inside thecylinder. In this embodiment, the cylinder on the moment bar may also behollow so it does not interfere with the hidden ball. The dual couplerball may be held in place with a removable pin that extends through theside of the hitch.

A cam on the foot of the jack reduces side forces and prevents the jackfrom binding. A cam at the moment bar jack interface reduces sliding andwear as the moment bar is raised.

Now referring to FIG. 1 , it shows a first embodiment using an electricjack as a lifting mechanism. A weight distribution system 101 couples avehicle 102 to a trailer 103. The system comprises a hitch receiver 104connected to the underside of the vehicle 102. Extending rearwardly fromthe hitch receiver 104 is a shank 105, a ball mount 106, and a ballwhich is partially hidden under the coupler of the trailer 107. Thehitch receiver 104, shank 105, ball mount 106, and ball are allconnected to the vehicle. On the trailer side of the system are acoupler 107, a frame 108, and a jack 109. The jack also contains a foot110. A moment bar 111 may be a part of the truck side of the system orthe trailer side of the system depending on user or manufacturerpreference. The jack has at least two positions, an up position and adown position. While the foot is down, the jack supports the weight ofthe trailer and its shaft is in compression. While it is up, the footabuts the underside of the moment bar 110 and the shaft is in tensionbetween the moment bar 111 and the frame 108. The jack also has usercontrols 112, which typically includes a switch or buttons to move thejack between position one and position two, or to an intermediateposition. That jack may be configured to weigh the load on the jack anddisplay the load on a load indicator 113. It may also communicate theload to a controller, such as a phone.

As depicted in FIG. 1 , when the system is in use to distribute the loadforward on the vehicle, an upward force 114 increases the tongue weight115 and imposes a moment 116 on the ball mount 106, which translatesthrough the vehicle 102, adding a downward force to the front tires andan upward force to the rear tires, balancing the vehicle.

Now referring to FIG. 2 , which shows a second embodiment that includesa bearing plate on the jack. A jack 201 is mounted to the frame of atrailer 202. The jack includes a hand crank 203 to raise and lower theshaft 204. A foot 205 caps the bottom of the shaft 204 and gives a jacka stable bearing surface for the ground. A bearing plate 206 is attachedto the shaft further up from the foot. In some embodiments, the bearingsurface is flat, however, the depicted embodiment shows a convexsurface. When the jack is in tension between the frame 202 and themoment bar 207, the convex shape of the bearing plate allows theabutting surfaces to roll slightly when the vehicle goes over bumps,rather than creating extreme point loads that an edge of a flat platewould create when the two surfaces are not parallel.

FIG. 2 also illustrates the way the moment bar 207 is locked onto thejack 201. In this configuration, the moment bar may be stored on thetrailer with less risk of theft. This is also beneficial to users whowould rather not have a moment bar or bars attached to their vehicles.However, other embodiments use moment bars that are easily removablefrom the jack, such as an open-ended bar that resembles a tuning fork.

Now referring to FIG. 3 , which illustrates a third embodiment of theway the system may attach to a ball mount and an alternativeconfiguration to abut the tension member. A hitch shank 301 is pinned toa ball mount 302 through a series of holes allowing the attachment to beadjustable. The upper end of the ball mount is attached to a ball 303for coupling to a trailer, whereas the lower end of the ball mountincludes a socket 304 designed to receive a moment bar 305. In thisconfiguration, the socket 304 pivots about a central pin 311. In otherconfigurations the socket does not rotate, but the moment bar rotateswithin the socket. The socket 304 includes an upper bearing surface anda lower bearing surface which translate the moment from the moment bar305 to the ball mount 302. They also may provide friction to assist withsway control for the trailer. The upper bearing surface and lowerbearing surface may be made of steel, for ease of manufacturing andcost, but they may also be made of other materials in order to providedifferent properties for the connection, such as rust prevention andfriction. A pin 309 keeps the moment bar 305 from slipping out of thesocket 304.

In the embodiment of FIG. 3 , the moment bar 305 has two prongs 306which abut a bearing surface on the jack 307. In the depictedembodiment, the bearing surface is provided by pegs, however, it mayalso be another shape such as the bearing plate of FIG. 2 , D-rings, orother.

Now referring to FIGS. 4 to 6 , a fourth exemplary embodiment of aweight distribution hitch system 400 is shown. The system uses atwo-part moment bar 401 with a first moment bar segment 402 thatattaches to a coupling 406 that attaches to the vehicle hitch (notshown) and a second moment bar segment 403 that is attached to thetrailer via bar chain 405. The first segment 402 and second segment 403are connected by spring 404. Spring 404 applies a biasing force on thesecond moment bar segment 403 such that it applies an upward force onthe coupling 406 and vehicle trailer hitch. The spring 404 also providesflexibility to the moment bar 401.

Now referring to FIG. 7 , a fifth exemplary embodiments, respectively ofa weight distribution hitch system 500 is illustrated. Moment bar 501 isused to apply a moment force on a vehicle via a trailer hitch 520. Theforce applied by moment bar 501 is adjusted using cable 507. In variousexemplary embodiments, the cable 507 is routed through guides 531 alongthe center of the trailer frame and/or guides 532 attached to the sidesof the trailer frame. The guides 532 may be part of brackets 533attached to the trailer.

Now referring to FIG. 8 , a sixth exemplary embodiments, respectively ofa weight distribution hitch system 600 is illustrated. Moment bar 601 isused to apply a moment force on a vehicle via a trailer hitch 620. Theforce applied by moment bar 601 is adjusted using cable 607. In variousexemplary embodiments, the cable 607 is routed through guides 631 alongthe center of the trailer frame and/or guides 632 attached to the sidesof the trailer frame. The guides 632 may be part of brackets 633attached to the trailer.

Now referring to FIGS. 9A to 9C, a seventh exemplary embodiment of atrailer hitch 720, with two interchangeable hitch balls 722 and 723.Different trailers may use different size hitches. Hitch 720 includesreversible hitch insert 721 with two different size balls 722 and 723.The hitch insert 721 may be removed from the hitch and its orientationreversed to select which hitch ball 722 or 723 is available for use. Ina preferred embodiment, the hitch ball 722 or 723 not in position foruse in concealed within cylindrical barrel 724 to which the momentbar(s) 701 may be attached, typically via a hitch coupling 706 thatmates with the barrel 724.

Now referring to FIG. 9C, an exploded view of a trailer hitch 720 withdual hitch balls 722 and 723 is provided. The hitch 720 may be detachedfrom the shank 726 reversible balls 721 removed to change which is inposition for use. In an exemplary embodiment a pin 725 or otherconnector is used to secure the hitch ball mount 722 to the hitch 720.

Now referring to FIGS. 10 to 10C, an eighth exemplary embodiment of ahitch coupling 806 is illustrated. Moment bars (not shown) connect tothe coupling via brackets 808 and, in an exemplary embodiment, aresecured thereto with a pin (not shown). The coupling 806 also includes abarrel 807 that attaches to the hitch (not shown) on the vehicle.

Now referring to FIGS. 11 , a ninth embodiment of a weight distributionhitch system that uses the trailer jack to apply the moment force isshown. The jack 910 includes a shaft 911 with a bearing plate 912 nearits foot. When the jack 910 is raised, the shaft 911 is retracted andthe bearing plate 912 contacts the moment bar applying a force throughthe bearing plate 912.

Now referring to FIGS. 12 to 15 , a tenth exemplary embodiment of aweight distribution hitch system using the jack to apply the momentforce. The jack shaft 1011 has a cam 1012 near the foot that contacts afirst moment bar 1002 applying an upward force on the second moment bar1003. The first and second moment bars are pivotally connected. In thisembodiment, the spring bar 1009 is attached to the trailer frame by achain 1005. Referring specifically to FIG. 13 , the positions of thefirst moment bar 1002 and second moment bar 1003 are better illustrated.The changed positions of the moment bars 1002 and 1003 with the jacklowered and raised are illustrated by FIGS. 12 and 14 , respectively.

Now referring to FIGS. 16 and 17 , an eleventh exemplary embodiment,which is an alternative to the embodiment of FIGS. 12 to 15 , is shown.The bearing plate 1112 comprises rounded cam 1113 that maintainsconsistent contact with the moment bars as the vehicle and trailertraverse rises and drops in the road without transferring the load to afront or back edge as would occur with direct contact on the bearingplate 1112 or using a more rectangular cam.

Now referring to FIG. 18 , a twelfth exemplary embodiment of a weightdistribution hitch system using the jack in compression to apply themoment force is shown. In various exemplary embodiments, the jack israised and then connected to the system. In some embodiments, as thejack 1210 is lowered a cable 1207 or similar connector is pulled downwith it. The cable is also attached to the moment bar 1201 in such a way(e.g., pulleys) such that it applies an upward moment force on themoment bar 1201.

Now referring to FIGS. 19 and 20 , a thirteenth exemplary embodimentusing the jack in compression rather than tension is shown. In thisembodiment, a cable 1307 (e.g., a steel braided cable) is attached tothe jack foot 1312 and routed to the moment bars 1301. In a preferredembodiment, the cable 1307 is routed between the frame and the momentbar 1301 as shown in FIG. 20 .

Now referring to FIGS. 21 and 22 , two exemplary embodiments of trailerswith weight distribution hitch systems with moment bar storage under thetrailer are shown. This prevents the moment bars from extending outwardand becoming an obstacle or hazard to persons walking around thetrailer. In FIG. 21 , the moment bars 1401 are stowed or docked underthe trailer using brackets 1427. In FIG. 22 , the moment bars 1501telescope in and out of brackets or sockets 1528 and are preferablylocked in place using pins or similar devices.

All patents, published patent applications, and other publicationsreferred to herein are incorporated herein by reference. The inventionhas been described with reference to various specific and preferredembodiments and techniques. Nevertheless, it is understood that manyvariations and modifications may be made while remaining within thespirit and scope of the invention.

What is claimed is:
 1. A weight distribution system used with a hitch ona vehicle and a trailer, the weight distribution system comprising: amoment bar with a forward end attached to the hitch so as to pivot abouta generally vertical axis, the moment bar extending rearwardly along acenter longitudinal plane of the trailer toward a rearward portion, themoment bar configured to exert a forward moment on the vehicle inresponse to an upward force on the rearward portion; a bracket attachedto a trailer frame element, wherein the bracket is above the rearwardportion and further from the center longitudinal plane of the trailerthan the rearward portion; and a tension member having a first end and asecond end, the tension member combined with a tension mechanism so asto increase and decrease a tensile force between the bracket and therearward portion, to thereby increase and decrease the upward force onthe rearward portion whereby sway of the trailer is reduced by biasingthe system back to the centerline when the vehicle and trailer are outof alignment; wherein the moment bar is disposed on a centerlongitudinal plane of the trailer.
 2. The system of claim 1, wherein thetension member is flexible.
 3. The system of claim 1, wherein thetension member is a cable.
 4. The system of claim 1, wherein the tensionmember is a chain.
 5. The system of claim 1, wherein the tensionmechanism comprises a threaded screw.
 6. The system of claim 1, whereinthe tension mechanism is a jack.
 7. The system of claim 1, wherein thetrailer frame comprises an A-frame, the rearward end of the moment baris disposed between two sides of the A-frame.
 8. The system of claim 1further comprising a first and second guide for the tension memberdisposed on the rearward portion of the moment bar, wherein the tensionmember communicates the force on the moment bar through the first guideand second guide.
 9. The system of claim 1, further comprising a secondbracket fixed to the frame of the trailer, wherein the first end of thetension member is attached to the first bracket and the second end ofthe tension member is attached to the second bracket and a middleportion of the tension member passes through a guide on the tensionmechanism.
 10. A weight distribution hitch system, comprising: a liftingmechanism; a moment bar having a forward portion pivotally connectedabout a vertical axis to a hitch coupling; and a linkage bar with a rearportion connected to the trailer and a front portion adapted to interactwith the lifting mechanism; wherein a rear portion of the moment bar ispivotally connected about a lateral axis to the linkage bar such thatwhen the lifting mechanism lifts on the front portion of the linkagebar, the rear portion of the moment bar is raised and induces a forwardmoment on the hitch coupling; and wherein the moment bar is disposed ona center longitudinal plane of the trailer.
 11. The system of claim 10,wherein the connection between the linkage bar and the moment bar arerearward of the lifting mechanism.
 12. The system of claim 10, whereinthe flexible tension member is a cable.
 13. The system of claim 10,wherein the flexible tension member is a chain.
 14. The system of claim10, wherein the lifting mechanism is a jack.
 15. The system of claim 10,wherein the lifting mechanism is a trailer jack.